Particularly in the last decades the thermal losses of the building heating were aimed to be reduced by coating their wall surfaces with panels made of material non-heat conductor, either synthetic material such as, e.g. polystyrene, or natural material such as, e.g., rock wool. These panels are placed adherent against the building wall surfaces, either on the outer side or on the inner building side and they form an insulation system that in the Italian jargon is called “cappotto” (coat).
The “cappotto”, carried out on the building inner or outer walls, is formed by panels of non-heat conductor, insulating material, sticked to the wall surface, on which a net of plastic material or a sheet of tar paper is carefully laid down and then a plaster layer, in turn covered by a thinner layer of plaster finish, i.e. a plaster having a thinner layer. The thickness of the “cappotto”, depending on its structure, can vary from 5 to more centimeters. On the elements forming the “cappotto”, a suitable layer of painting product of the desired colour is finally applied.
The insulation method by means of the “cappotto” application can be carried out either on new construction buildings or on existing buildings. This system had a positive result as concerns the heat losses from the buildings, which are reduced, but showed some inconveniences, such as:                the wall surfaces, formed with a “cappotto” covering, are mechanically weak: they are scarcely resistant to the knocks and little suitable to be loaded with objects of heavy weight. In case of “cappotto” carried out on the inner side, it can be uncertain that they may hold up objects such as pictures or lamps;        structural modifications always become necessary in case of inner “cappotto”, because of the changes of the walls as regards thresholds, frames, corners;        the insulation material does not allow the wall surface to breathe and therefore a humidity increase inside the building takes place with consequent mould formation, so causing compulsory the carrying out of openings for the air transit from outside;        difficulties of installation in historical city-centres, particularly as regards the carrying out of a “cappotto” on the building outer surface;        long time application and, consequently, high costs,furthermore, and of particular importance:        the toxic effect due to the degradation that takes place, in time, of the materials forming the insulating panels: this is valid for the polystyrene, that can lead, in time, to cancerogenic monomers as well as for the rock wool, that can form, in time, fibrous material;        difficult disposal of said insulating materials at the end of their life, that is, in the average, longer than ten years from their production.        
More recently thermal paints have been studied and produced that contain hollow ceramic microspheres.
The use of said paints to a wall surface does not reduce the thermal conductivity, but it limits the heat transit through the wall surface because of the thermal reflectance, even if the thermal conductivity is reduced in a relatively modest measure. This last solution provides, however, good results being the applied paint in a limited thickness and not involving the presence of potentially toxic materials.